Tyre sizes front to rear

Wagonman · Post by **Wagonman** » Sun Jul 01, 2012 2:11 pm

I just got a 97 Liberty LX Awd WOOT! But it needs front tyres.

They are 205/55R16 and i got some other tyres that are 205/60R16 that i want to put on. Im having a mental blank and cant work out if that will all sweet with the awd system. It doesnt have LSDs as far as i am aware (i only just got it yesterday!) and im not familiar with the drivetrain yet. Is it the same-ish to an L series but constant AWD?

Gannon · Post by **Gannon** » Sun Jul 01, 2012 2:40 pm

Running those different sized tyres will kill your centre diff (which is an LSD) in a short amount of time.

Ratbag · Post by **Ratbag** » Sun Jul 01, 2012 4:14 pm

Gidday WM

Congrats.

Make that "kill your centre diff in a VERY short amount of time" ...

Probably within around 50 to 200 kms, max.

Subaru even specifically instruct us not to run different makes of tyres, or the same makes with different wear patterns ...

Our AWD vehicles might look much like any other, but connect all four wheels together as a driving set, and it makes for very specific requirements as regards taking good care of them ...

Same with 4WD vehicles, except different (i.e. those with a transfer case in the middle, rather than having a diff in the middle) - if you drive these on hard surfaced roads in 4WD high or low range, whether on dirt or bitumen, you will either throw a drive shaft (usually the front one ... ), or break your transfer case.

Ratbag · Post by **Ratbag** » Sun Jul 01, 2012 4:26 pm

now is the time ..

RSR 555 · Post by **RSR 555** » Mon Jul 02, 2012 7:15 am

Pretty much what these guys said Johnny.. Try and buy all 4 tyres and rotate them as much as possible to give you an even wear pattern.

Just checking but are you 100% sure it's AWD? as not to many LX models were.

guyph_01 · Post by **guyph_01** » Mon Jul 02, 2012 2:11 pm

Hahaha, More money to spend. and no sry i don't have a set....

Wagonman · Post by **Wagonman** » Mon Jul 02, 2012 7:32 pm

Lol shut up Guy!! Yeah its a LX but i have a feeling it has been converted from an auto to manual at the very least. Or its imported?? Has legacy written on the boot..

taza · Post by **taza** » Mon Jul 02, 2012 8:35 pm

I ran an odd size spare on my Forester for about 20-30km and there wasn't even much difference in the size. Caused the centre diff to whine like a bitch in my old gearbox. Never do it with an AWD unless your loaded with $$..

guyph_01 · Post by **guyph_01** » Mon Jul 02, 2012 9:07 pm

taza wrote:I ran an odd size spare on my Forester for about 20-30km and there wasn't even much difference in the size. Caused the centre diff to whine like a bitch in my old gearbox. Never do it with an AWD unless your loaded with $$..

DO IT, DO IT, Don't worry, i've got a few diff's and gearbox i can sell you when you break yours:D HAHAHAHAHAHAHA

Wagonman wrote:Lol shut up Guy!! Yeah its a LX but i have a feeling it has been converted from an auto to manual at the very least. Or its imported?? Has legacy written on the boot..

Or they bought a badge off ebay, or a boot from the wreakers:)

If it was auto on the driver side shock tower, in the engine bay, if you see and little black fuse close to the top of the shock hat then you know if was auto.

RSR 555 · Post by **RSR 555** » Mon Jul 02, 2012 10:16 pm

guyph_01 wrote:If it was auto on the driver side shock tower, in the engine bay, if you see and little black fuse close to the top of the shock hat then you know if was auto.

Only if the car was an AWD auto.

Johnny... can you take some pics of the compliance plates under the bonnet and PM me them.

Wagonman · Post by **Wagonman** » Wed Jul 04, 2012 12:52 am

When i get the time ill make a dedicated thread for my cars with pics and also paul ill send you a pic of the compliance plate if i get to it before i see you next.

Brumby Kid · Post by **Brumby Kid** » Wed Jul 04, 2012 10:20 am

The different size of tyres you have.
I thought it was the width that was different, not the height or rolling size.
205/55 rim 16"
205/60 rim 16"

Shouldn't this be ok?

Wagonman · Post by **Wagonman** » Wed Jul 04, 2012 8:40 pm

205 is the width and 55 is a pencentage of the width. This will effect the overall diametre and cause damage..

Does anyone know how much you can get away with before it becomes an issue for the gearbox?
Theres about 10mm difference between those two sets of tyres (if ive done my rough calculations right). Then instead you have slightly bald tyres on the front and tyres with 5mm tread on the rear, would that be an issue when theres only 5mm difference between those two scenarios?? Hypotheticly speaking..

Subyroo · Post by **Subyroo** » Wed Jul 04, 2012 11:17 pm

Wagonman wrote:205 is the width and 55 is a pencentage of the width. This will effect the overall diametre and cause damage..

Does anyone know how much you can get away with before it becomes an issue for the gearbox?
Theres about 10mm difference between those two sets of tyres (if ive done my rough calculations right). Then instead you have slightly bald tyres on the front and tyres with 5mm tread on the rear, would that be an issue when theres only 5mm difference between those two scenarios?? Hypotheticly speaking..

Check out this thread Wagonman:

showthread.php?t=21272&highlight=tyres

Wagonman · Post by **Wagonman** » Thu Jul 05, 2012 12:51 am

Cheers Subyroo, that was very helpful.

In the end i think it was decided that up to 4% difference of the tyre circumference between each tyre is acceptable to keep your drivetrain in good condition.

As in;
If the rolling distance of tyre 1 is 100cm then the rolling distance of tyres 2,3,4 should be within 4cm of each other.

Post by **Alex** » Thu Jul 05, 2012 8:29 am

It's not worth the risk imho. Tyres are way cheaper than gearboxes and diffs

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Brumby Kid · Post by **Brumby Kid** » Thu Jul 05, 2012 8:49 am

So if my tyres are
175/75/13
What does this mean?
I thought it was
Overall diameter(often in inches) / width / rim size.

Cheers Cam

Ratbag · Post by **Ratbag** » Thu Jul 05, 2012 9:28 am

Brumby Kid wrote:So if my tyres are
175/75/13
What does this mean?
I thought it was
Overall diameter(often in inches) / width / rim size.

Cheers Cam

That's tyre width/profile/rim diameter ...

From my Batphone

Brumby Kid · Post by **Brumby Kid** » Thu Jul 05, 2012 9:45 am

Picture showing whys what?
Just to clarify we're talking about the same things.

Cheers Cam

RSR 555 · Post by **RSR 555** » Thu Jul 05, 2012 10:46 am

Brumby Kid wrote:So if my tyres are
175/75/13
What does this mean?
I thought it was
Overall diameter(often in inches) / width / rim size.

Cheers Cam

175 = 175mm - this is the 'width of the thread', width of the tyre from inside to outside (sidewall to sidewall)

75 = 75% -this is height of the tyre. It's a percentage of the width (i.e. 175 x 75% = 131.25mm)

13 = 13 inch - this is the size of the rim

Here is a good calculator for when fitting larger rims. It allows you to keep your speedo in check.
http://www.miata.net/garage/tirecalc.html

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Tyre sizes front to rear

Tyre sizes front to rear

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